PSLE Maths question. How to solve?

[Ender]

This is a similarity question asked before they've learned about similarity (Secondary subject). Volume ratios are the cube of the side ratios.

 

Anyway they've done basic algebra in P6, so just say that small cuboid volume is xyz but large cuboid volume is (2x)(2y)(2z)=(2)(2)(2)xyz = 8xyz. That's how you get eight times lol.

Trust you to come out with the mathematical proof.

[1fast1]

Trust you to come out with the mathematical proof.

Haha. Get em while they're young, is what I say. All this nonsense about units and blocks just rots the brain. It's as much math as physics is about feelings and motivations of particles.

[Ender]

hmmm...make sense.

 

2U : 1U  --> 4x4x4  : 2x2x2

=

64 : 8 ( 8 times bigger)

 

hence 348/8 = 48.

 

U are really good in P6 Maths. Thanks.

Last time my son was P6, I have to do the other schools exam paper together with him.. Now I drop to P4 standard liao, coz my daughter is in P4, and I am giving her the same math training as I gave my son.

[mersaylee]

This is a similarity question asked before they've learned about similarity (Secondary subject). Volume ratios are the cube of the side ratios.

 

Anyway they've done basic algebra in P6, so just say that small cuboid volume is xyz but large cuboid volume is (2x)(2y)(2z)=(2)(2)(2)xyz = 8xyz. That's how you get eight times lol.

Whenever I see math question I need the green

Whenever I see explanation by others I need the blue

Whenever I see your post... 2 packs of red also not enough to cure the migraine

[1fast1]

Whenever I see math question I need the green

Whenever I see explanation by others I need the blue

Whenever I see your post... 2 packs of red also not enough to cure the migraine

Lol!!

[Hiphiphoray]

If u have problems with P6 Maths Q, just drop a message.

 

I should be able to help out a bit. (should only....haha)

 

So far I have prepared worked solutions for 20 SA2 schools for 2018/2017. Plus complete 2016 to 2018 PSLE Q as well.

 

Gone to hell and back to do this !!!!

 

By far, the most lengthy and difficult to absorb Q is listed below....took quite a while for my P6 son to absorb it.

 

Nanyang / 2017 / Q17

 

At first, Box M had 18 pears and 42 lemons while Box N had 36 pears and 50 lemons.

Then, some lemons were moved from Box M to Box N and some pears were moved from Box N to Box M.

In the end, Box M contained pears and lemons in the ratio 3 : 4 while Box N contained pears and lemons in the ratio 1 : 2.

 

a) In the end, how many lemons were there in Box M ? ( 4 marks)

 

b) In the end, how many more pears did Box N contain than Box M ? (1 mark)

 

 

 

Last time my son was P6, I have to do the other schools exam paper together with him.. Now I drop to P4 standard liao, coz my daughter is in P4, and I am giving her the same math training as I gave my son.

 

[Ender]

Following Primay school syllabus, I apply 3 techniques that were taught in school. This is also how I teach my kids.

1. Recognise there is a constant total situation (somewhere in P4 they were taught this, and others like constant difference))

2. Apply the common factors for the ratio correctly. (either P4 or P5 they were taught)

3. Simultaneous Equation (teach in P6)

 

Teach the student to recognise where is the "constant total". i.e for this question, regardless the before and after the movement of fruits, the total for Pear and Lemon is constant.

 

Total Pears = 18 + 36 = 54

Total Lemons = 42 + 50 = 92

 

Apply the U and P as common factors for ratio problems. In this case I call it M and N to refer to the boxes naming,

Final Pear: Lemon ratio for 

Box M -> 3M : 4M

Box N -> 1N : 2N

 

Use Simultaneous equation for the constant total found earlier. This will be taught is P6.

3M + 1N  = 54 ----(1)  (X2)=> 6M + 2N = 108 ---(2)

 

4M + 2N = 92 -----(3)

 

(2) - (3)

2M = 16

M = 8

 

Subsitute M into any one of the above equations to solve for N

N = 30

 

1) In the end, lemons in box M = 4M = 32 ##

 

2) Pears in box M = 3M  =24

Pears in box N = 1N = 30

how many more pears = 30 - 24 = 6 ## 

 

Edited May 23, 2019 by Ender

[13177]

Whenever I see math question I need the green

Whenever I see explanation by others I need the blue

Whenever I see your post... 2 packs of red also not enough to cure the migraine

Whenever i see math question, any type of panadol also no use.